Well drilling tool



June 16, 1936. J. H. HOWARD WELL DRILLING TOOL Original Filed May 13, 1933 0 2 w M a .W M 3 E a 2 4 .mfi. v N H, L n .w L .5 ,0 4 m m a; B y a x a, W x u w W M X 3 z\ ,A 4 w 4 v .2 5 4 7 H 3 3 2 A 35% 4 a gain 4 m E Arroewr Patented June 16, 1936 UNITED sTAres .PA'E'E FFEQE.

WELL DRILLINGr TOOL Original application May 13, 1933, Serial No. 670,845. Divided and this application April 1, 1935, Serial N0. 14,118

10 Claims.

'This invention relates to a well drilling tool and relates more particularly to a rotary drill bit for use in the rotary method of well drilling. A general object of this invention is to provide a well drilling bit involving novel, simplified and particularly effective means for rotatably mounting or supporting the cutters.

This application is a division of my application for Letters Patent Serial No. 670,845,- entitled Well bit. 7

Another object of the invention is to provide a well bit including a roller cutter and a novel means for discharging the rotary mud or circulation fluid from the lower end of the cutter at a high velocity without subjecting the cutter to the eroding action of the sand or solid matter in the fluid.

Another object of the invention is to provide a roller bit including simple and effective means for rotatably mounting the cutters that permit the easy and quick replacement of thecutters and that effectively support the cutters against Iongitudinal strains.

Another object of the invention is to provide a means for rotatably mounting the cutter of a well bit involving wear plates and bushings on the cutter carrying pins that may be easilyand quickly replaced when the cutters are removed from the pins.

A further object of the invention is to provide a cutter mounting of the character mentioned in which a replaceable thrust washer or wear plate acts as a choke or nozzle for the lower end of a fluidpassage discharging at the lower end of the cutter.

Other objects and features of the invention will be fully understood from the following detailed description of a typical form and application of the invention, throughout which description reference is made to the accompanying drawing, in which:

Fig. 1 is a front elevation of the bit provided by the invention showing it in one-quarter longitudinal cross section. Fig. 2 is a side elevation of the bit, and Fig. 3 is a longitudinal or vertical detailed sectional view of one of the cutters and its mounting means.

The bit includes, generally, a shank or body I 0, cutters II and means X for rotatably mounting the cutters I I on the lower end of the body.

In accordance with the broader principles of the invention the shank or body ll! of the bit may be varied considerably in shape. In the particular case illustrated the body I 0 includes an upper cylindrical portion 12 and two enlargements or bosses l3 at its lower end. The body I0 is adapted to be operated on the lower end of a string of drill pipe, or the like, and a tapered screw threaded pin I4 is provided on the upper end of theportion l2 to facilitate connection of the body with a drill collar or other part of an operating string. The bosses l3 constitute the lower portion of the body l0, and are inclined downwardly and rearwardly. relative to the forward-direction of rotation of the bit. The lower ends l5 of the bosses l3 are fiat and are normal to the inclined axes of the bosses. The bosses l3 project outwardly from substantially diametrically opposite sides of the body l0.

The cutters II are in the nature of roller cutters rotatable about inclined axes at the lower end of the bosses I.'i.- The cutters-ll and their dispositions are fully claimed in the above-mentioned co-pending application. The bodies of the cutters H are substantially cylindrical in their general configuration and have flat upper 0 ends. Central longitudinal sockets 30 extend into the cutters H from their upperends. The sockets 30 have cylindrically curved side walls and flat bottoms or inner ends.

. Each cutter l I is provided with a set or series of reaming cutting parts 4!] and a plurality of lower cutting parts or teeth M for acting on the formation at the bottom of the well bore. The reaming parts 40 operate to shear or cut away the formation at the side walls of the well bore 30 and to feed or urge the cutters downwardly. The reaming parts lll are in the nature of a plurality of longitudinally spaced annular ridges or sharpened flanges surrounding the upper portions of the cutters H. The tops or upper sides of' the 35 reaming parts 40 are flat and lie in planes substantially normal to the axes of rotation of the cutters II. The lower sides of the reaming parts 40 are inclined downwardly and inwardly and almost join the upper sides of the reaming parts 40 at their peripheries to provide them with comparatively sharp cutting edges 49 When the bit is operated, the body it) is rotated in a forward or clockwise direction and the engagement of the cutters l l with the formation 45 causes them to independently rotate in a counter clockwise direction. The reaming parts 40 cut a thread or a plurality of grooves in the wall of the well bore and the rotation of the cutters ll causes the reaming parts to shear off the earth 50 or formation between the thread or grooves they have formed by moving upwardly due to the rearward and downward inclination of the cutters. This threading or cutting of the reamingparts 40 into the side walls of the well bore tends to force or urge the cutters ll downwardly so as to maintain the teeth 4| in effective cutting engagement with the formation at the bottom of the bore. The inclined lower sides of the reaming parts 40 provide for the ready cutting or threading of the parts into the formation, while the flat upper sides of the parts terminating in the outer peripheral edges 4|] are effective in shearing or cutting away the formation between the threads or cuts.

The lower cutting parts or teeth 4| project downwardly from the lower ends of the cutters II and are operable to act on the formation at the bottom of the bore. There is a plurality of circumferentially spaced teeth 4| on each cutter The cutting teeth 4| extend longitudinally of the cutters and have their upper ends spaced below the lowermost reaming parts 40. The teeth 4| project radially outward from the bodies of the cutters II and have outer cutting edges 42 inclined downwardly and slightly inwardly. The lower portions of the teeth 4| projecting from the lower ends of the cutters converge inwardly toward the centers of the cutters and have their inner ends 43 spaced from the central axes of the cutters. The cutting teeth 4| are operable to engage the formation at the bottom of the well bore and operate to cause rotation of the cutters. As the cutters l rotate about axes inclined downwardly and rearwardly relative to the direction of rotation of the bit, the teeth 4| are dragged across the formation at the bottom of the bore to have a shearing or dragging action.

The cutter mounting means X includes stems or pins I5 for rotatably carrying the roller cutters The pins l6 have longitudinally'tapered upper portions I8 and cylindrical lower portions IQ for carrying the cutters The tapered upper portions I8 of the cutter carrying pins are carried in correspondingly shaped openings 20 in the bosses 3. The openings 20 extend upwardly in the bosses from their lower ends I 5 and their axes are inclined downwardly and rearwardly relative to the direction of rotation of the bit and are normal to the lower ends l5 of the bosses. In the particular case illustrated in the drawings, the axes of the pin carrying openings 20 are inclined at approximately to a vertical plane including the central longitudinal axis of the body I0.

Means are provided for removably or detachably retaining the cutter carrying pins 6 in the openings 20. Transverse openings 2| are provided in the bosses and intersect the openings 20. The openings 2| are rectangular or elongate in transverse cross section and their major cross sectional axes are tipped or inclined at slightly greater angles than the walls of the tapered openings so that the upper portions of the openings 2| intersect the openings 20, while the lower portions of the openings 2| merely join the openings 20. The openings 2| are comparatively narrow and are longitudinally tapered or of diminishing cross section. Notches 22 are provided in the tapered portions |8 of the cutter carrying pins to register with the openings 2| where they intersect the openings 20. Retaining members or wedges 23 are driven through the openings 2| to cooperate with the notches 22 in the pins I6. The inclination of the openings 2| and their tapering walls cause the wedges 23 to force the pins |6 upwardly into the openings 20. The retaining members or wedges 23 are comparatively thin and are sufliciently long so that their small ends project from the openings 2|. The projecting small ends of the wedges may be distorted or bent over to prevent accidental displacement of the wedges. It will be apparent how the wedges 23 may be driven from the openings 2| to permit the removal of the cutter carrying pins Hi from the: openings 20.

The lower portions |9 of the pins l6 carrying the cutters l project downwardly from the lower ends |5 of the bosses |3 to rotatably support or carry the cutters at the lower end of the body I0.- An annular radial flange 25 is provided on each pin IS on the upper end of its cutter carrying portion I9. The flanges 25 are received in the sockets or enlargements 3| of the openings 30. It is a feature 01 the present invention that wear plates and bushings are provided on the pins l6 that are capable of being replaced so that the cutter carrying pins do not require early replacement, Tubular bushings 25 surround the cylindrical portions 9 of the cutter carrying pins and extend'from the flanges 25 to the lower ends of the pins. The bushings 26 are; of course, engaged by the walls of the openings 30. Thrust plates or wear plates 2'! are provided on the flat lower ends of the pins IS. The plates 21 may be detachably connected to the pins and held against rotation by dowels 28. The'lower walls of the cutter openings 30 bear upwardly against the plates 21.

The invention provides novel and effective means for removably retaining the cutters II on the pins l6 and for transmitting longitudinal thrusts from the cutters'to the pins. The'means X includes a lock ringor retaining ring 32 atc tached to the upper end of each cutter II by screws 33. The attaching members or screws 33 may be retained against displacement by spot welding. The rings 32 project inwardly over the flanges 25 and washers 34 are interposed between the rings 32 and the flanges. Therings 32 positively hold the cutters against downward movement on the pins l6 and areadapted to transmit downward thrusts from the cutters to the pins.-

The invention includes means for discharging circulation fluid from the lower ends of the cutters A central fluid passage extends downwardly into the upper end of the body" l0.

Branch passages, 5| extend downwardly and outwardly from the main passage 50 to the upper 0 ends of the openingsZU; The cutter carrying pins l6 are tubular, being provided with central longitudinal openings 52. Enlargements 53 are provided in the lower ends of the passages 52,

and the replaceable plates 21 are provided with bosses or nozzle parts 54 which have flanges received in the enlargements 53. The nozzle parts 54 may be integral with the plates 21 or may be separable members as illustrated.- In the construction illustrated the nozzle parts 54 extend through central openings in the plates 21. Restricted fluid openings 55 are provided in the nozzle parts 54 to discharge the circulation fluid downwardly through central openings 55 in the lower ends of the cutters The comparatively small nozzle openings 55 materially increase the velocity ofthe circulation fluid as it is discharged under pressure from the lower ends of the cutters. duced 'diarrieter extends downwardly from the main 'fluid'pas'sage 50 to discharge from the lower end of the body II] at a point between the cutters I;

It is believed that the operation of the roller A central fluid discharge passage of 'r-ebit provided by the invention will be readily apparent from the foregoing detailed description. During operation of the bit, the engagement of the teeth 4| with the formation causes the cutters l I to be rotated in a counter clockwise direction. The reaming parts 40 of the cutters cut into the formation at the side wall of the well bore to form threads or circular cuts, and the advancing and rotating cutters cause the reaming parts 40 to shear ofi the formation between the threads or cuts thus formed. The teeth 4| on the downwardly and rearwardly inclined cutters are effective in cutting away the formation at the bottom of the well bore as they are dragged over the surface of the formation during the rotation of the bit. The combination of the annular reaming parts 40 and the radial circumferentially spaced teeth 4| on the downwardly and rearwardly inclined cutters ll produce a very rapid and efiicient cutting action, and insures the smooth steady operation of the bit.

The cutter carrying pins l6 are detachably connected with the body ID, by the wedges 23, so that they cannot become accidently displaced during operation. The wedges 23 may be easily removed when it is desired to detach the cutter assemblies for replacement of the cutters or other parts. The cutters ll may be easily dismounted from the pins l6 by removing the rings 32. The bushings 26 and plates 21 take the wear on the pins and may be replaced when worn. The provision of the wear taking bushings 26 and plates 21 permits the pins IE to be used to carry the new or replacement cutters. The flanges 25 and rings 32 provide comparatively large thrust surfaces for taking the downward thrusts on the cutters, while the upward thrusts are taken by the washers 21. The circulation fluid in being discharged downwardly and rearwardly from the lower ends of the cutters ll during the rotation of the drill, effectively flushes the cutters and causes considerable turbulence. in the lower end of the well bore. The circulation fluid discharging from the central outlet 60 efiectively washes the reaming parts 40. The nozzle parts 54 may be replaced from time to time as they may be worn by the abrasive action of the solid matter in the circulation fluid. The bit provided by the present invention is extremely simple and inexpensive of manufacture, and is rapid and effective in its operation.

Having described only a typical form and application of my invention, I do not wish to be restricted to the form and application herein set forth, but wish to reserve to myself any modifications or variations that may appear to those skilled in the art or fall within the scope of the following claims.

Having described my invention, I claim:

1. A well bit including, a body to be rotated in a well bore, a roller cutter on the lower end of the body rotatable about an axis inclined downwardly and rearwardly relative to the direction of rotation of the body, cutting parts on the cutters, and means for discharging fluid downwardly and rearwardly from the lower end of the cutter.

2. A well bit including, a body to be rotated in a well bore, a pin projecting downwardly from the lower end of the body, a roller cutter having a socket receiving the projecting portion of the pin, the pin having a fluid passage and the cutter having a fluid discharge opening, and a plate on the lower end of the pin engageable by the bottom wall of the socket, the plate having a restricted opening to discharge-fluid from said passage through the opening in the cutter.

3. A well bit including, a body to be rotated in a Well bore, a pin projecting downwardly from the lower end of the body, a roller cutter having a socket receiving the projecting portion of the pin, the pin having a fluid passage and the cutter having a fluid discharge opening, and a plate on the lower end of the pin engageable by the bot- TO tom wall of the socket, the plate having a nozzle portion discharging fluid from the lower end of said passage through said opening at an increased velocity.

4. A well bit including, a body having an open- 15 ing in its lower end, a removable pin in the opening having a substantially cylindrical portion projecting from the lower end of the body, a roller cutter having a substantially cylindrical socket rotatably receiving the projecting portion of the 20 pin, replaceable bushings on the periphery of the projecting portion of the pin and the lower end of the pin, and means for removably retaining the cutter on the pin including a radial flange on the pin, and a detachable part on the cutter 25 for transmitting downward thrusts from the cutter to the flange.

5. A well bit including, a body, a removable pin projecting from the lower end of the body, a roller cutter having a socket rotatably receiving the projecting portion of the pin, there being a longitudinal fluid passage in the pin, the body having a fluid passage to supply fluid to the passage in the pin, there being a discharge opening in the lower end of the cutter, and a thrust washer at the lower end of the pin having an enlarged portion with a restricted opening for discharging fluid from the passage of the pin through the opening in the cutter.

6. A well bit including a body, a pin projecting from the lower end of the body, a rotatable cutter having a socket for receiving the projecting portion of the pin, the pin having a longitudinal fluid passage and the cutter having a fluid discharge opening, a removable thrust plate on the lower end of the pin engageable by the bottom wall of the socket, the plate having a restricted opening to discharge fluid from said passage through the opening in the cutter at an increased velocity and means for holding the plate against rotation.

7. A well bit including a body, a pin projecting from the lower end of the body, a rotatable cutter having a socket for receiving the projecting 55 portion of the pin, the pin having a longitudinal fluid passage and the cutter having a fluid discharge opening, a removable thrust plate on the lower end of the pin engageable by the bottom wall of the socket, and nozzle means on the plate to discharge fluid from said passage through the opening in the cutter at an increased velocity.

8. A well bit including a body, a pin projecting from the lower end of the body, a rotatable cutter having a socket for receiving the projecting portion of the pin, the pin having a longitudinal fluid passage and the cutter having a fluid dis charge opening, a removable thrust plate on the lower end of the pin engageable by the bottom wall of the socket, and a thickened portion on the plate having a nozzle part of less diameter than said passage and said opening for discharging fluid from said passage through the opening in the cutter.

9. A rotary well bit including a body having an opening in its lower end, a removable pin retained in the opening and having a portion projecting from the lower end of the body, a flange on said portion, a rotatable cutter having a socket rotatably receiving said-portion and its flange, and means retaining the cutter on the pin including a part secured to the upper end of the cutter and adapted to bear on the lower end of the body, and a washer interposed between the lower side of said part and the upper surface of the flange.

10, A rotary well bit including a body having upper end of the cutter to bear on the lower end 10 of the body.

JOHN H. HOWARD. 

